Naphthalocyanine derivatives

Abstract

The present invention relates to the use of specific naphthalocyanine chromophores with different axial substituents as almost colourless IR absorbers for security printing applications.

The invention claimed is: 
     
       1. A method for security printing, the method comprising:
 contacting a printing ink formulation comprising a compound with a substrate, 
 wherein the compound is represented by the following formula (Ia) or the following formula (Ib): 
 
       
         
           
           
               
               
           
         
         wherein 
         X is O(C 2 H 4 O) n CH 3 , OC 8 -C 18 alkyl, or OSi(n-C 1 -C 12 alkyl) 3 ; 
         n is a integer from 1 to 6; 
         M 2 , M 3  are Ga; 
         B 1  in the formula (Ib) is C 1 -C 12 alkylene, C 1 -C 12 alkylene which is interrupted by one or more oxygen atoms or C 1 -C 12 alkylene which is substituted by at least one OH group; 
         R 20  and R 21  are independently of each other H, F, OR 16 , SR 16 , NHR 17 , or NR 17 R 17′ ; 
         R 16  is C 1 -C 12 alkyl, (C 2 H 4 O) n OR 18 , or phenyl; 
         R 18  is C 1 -C 12 alkyl; and 
         R 17  and R 17′  are independently of each other C 1 -C 12 alkyl, (C 2 H 4 O) n OR 18 , or phenyl; or 
         R 17  and R 17′  together optionally represent a 5- or 6-membered aliphatic ring, wherein one C-atom in the 5- or 6-membered aliphatic ring is optionally replaced by oxygen, to form a pyrrolidine, piperidine, 2-methylpiperidine or morpholine radical, and 
         wherein the compound has a mean particle size of from 15 nm to 1000 nm. 
       
     
     
       2. The method according to  claim 1 , wherein X is O(C 2 H 4 O) n CH 3  and n is 3 or 4. 
     
     
       3. The method according to  claim 1 , wherein B 1  in the formula (Ib) is —CH 2 —CH 2 — or —CH 2 —HC(OH)—CH 2 —. 
     
     
       4. The method according to  claim 1 , wherein R 20  and R 21  are independently of each other H or OR 16  and R 16  is C 1 -C 12 alkyl. 
     
     
       5. The method according to  claim 1 , wherein the printing ink is a non-aqueous printing ink. 
     
     
       6. The method according to  claim 1 , wherein the method improves a property of a print. 
     
     
       7. A printing ink, comprising:
 a) at least one compound selected from the group consisting of a compound of the following formula (Ia) and a compound of the following formula (Ib): 
 
       
         
           
           
               
               
           
         
         wherein 
         X is OH, O(C 2 H 4 O) n CH 3 , OC 8 -C 18 alkyl, or OSi(n-C 1 -C 12 alkyl) 3 ; 
         n is a integer from 1 to 6; 
         M 2 , M 3  are Ga; 
         B 1  in the formula (Ib) is C 1 -C 12 alkylene, C 1 -C 12 alkylene which is interrupted by one or more oxygen atoms or C 1 -C 12 alkylene which is substituted by at least one OH group; 
         R 20  and R 21  are independently of each other H, F, OR 16 , SR 16 , NHR 17 , or NR 17 R 17′ ; 
         R 16  is C 1 -C 12 alkyl, (C 2 H 4 O) n OR 18 , or phenyl; 
         R 18  is C 1 -C 12 alkyl; and 
         R 17  and R 17′  are independently of each other C 1 -C 12 alkyl, (C 2 H 4 O) n OR 18 , or phenyl; or 
         R 17  and R 17′  together optionally represent a 5- or 6-membered aliphatic ring, wherein one C-atom in the 5- or 6-membered aliphatic ring is optionally replaced by oxygen, to form a pyrrolidine, piperidine, 2-methylpiperidine or morpholine radical, 
         b) at least one polymeric binder, 
         c) optionally at least one organic solvent, 
         d) optionally at least one colorant, 
         e) optionally at least one further additive, and 
         f) optionally at least one photoinitiator, and 
       
       wherein the at least one compound a) has a mean particle size of from 15 nm to 1000 nm. 
     
     
       8. The printing ink according to  claim 7 , comprising:
 from 0.0001 to 25% by weight of the at least one compound a), 
 from 5 to 75% by weight of the at least one polymeric binder b), 
 from 0 to 94.9999% by weight of the at least one organic solvent c), 
 from 0 to 25% by weight of the at least one colorant d), and 
 from 0 to 25% by weight of the at least one further additive e), 
 wherein the sum of components a) to e) adds up to 100%. 
 
     
     
       9. A process for manufacturing a security document, the process comprising:
 printing on a substrate with the printing ink formulation according to  claim 7 . 
 
     
     
       10. A security document, comprising a substrate and a cured ink,
 wherein the cured ink comprises at least one compound selected from the group consisting of a compound of the following formula (Ia) and a compound of the following formula (Ib): 
 
       
         
           
           
               
               
           
         
         wherein 
         X is O(C 2 H 4 O) n CH 3 , OC 8 -C 18 alkyl, or OSi(n-C 1 -C 12 alkyl) 3 ; 
         n is a integer from 1 to 6; 
         M 2 , M 3  are Ga; 
         B 1  in the formula (Ib) is C 1 -C 12 alkylene, C 1 -C 12 alkylene which is interrupted by one or more oxygen atoms or C 1 -C 12 alkylene which is substituted by at least one OH group; 
         R 20  and R 21  are independently of each other H, F, OR 16 , SR 16 , NHR 17 , or NR 17 R 17′ ; 
         R 16  is C 1 -C 12 alkyl, (C 2 H 4 O) n OR 18 , or phenyl; 
         R 18  is C 1 -C 12 alkyl; and 
         R 17  and R 17′  are independently of each other C 1 -C 12 alkyl, (C 2 H 4 O) n OR 18 , or phenyl; or 
         R 17  and R 17′  together optionally represent a 5- or 6-membered aliphatic ring, wherein one C-atom in the 5- or 6-membered aliphatic ring is optionally replaced by oxygen, to form a pyrrolidine, piperidine, 2-methylpiperidine or morpholine radical, and 
         wherein the at least one compound has a mean particle size of from 15 nm to 1000 nm. 
       
     
     
       11. The security document according to  claim 10  obtained by a printing process, wherein a printing ink formulation comprising the at least one compound is used. 
     
     
       12. The security document according to  claim 10 , which is selected from the group consisting of a bank note, a passport, a check, a voucher, an ID- or transaction card, a stamp and a tax label. 
     
     
       13. The security document according to  claim 10 , which is part of a rigid or flexible packaging, of a carton board or of a brand or product label.